<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>border</title>
  <style>
    .triangle {
      width: 0;
      border: 30px solid transparent;
      border-color: aquamarine antiquewhite aliceblue azure;
    }
    .triangle2 {
      width: 0;
      border: 30px solid transparent;
      border-width: 80px 30px;
      border-top-color: aquamarine;
    }
    .triangle3 {
      width: 0;
      border: 30px solid transparent;
      border-width: 80px 30px;
      border-top-color: aquamarine;
      border-right-color: aquamarine;
    }
    .triangle4 {
      position: relative;
      width: 60px;
      height: 160px;
      overflow: hidden;
    }
    .triangle41 {
      position: absolute;
      top: 0;
      right: 0;
      width: 0;
      border: 30px solid transparent;
      border-width: 80px 30px;
      border-top-color: aquamarine;
      border-right-color: aquamarine;
    }
    .triangle42 {
      position: absolute;
      top: 0;
      right: 0;
      width: 0;
      border: 30px solid transparent;
      border-top-color: #fff;
      border-right-color: #fff;
      border-width: 100px 10px;
    }
    .circle {
      width: 200px;
      height: 200px;
      border-radius: 50%;
      background-color: antiquewhite;
    }
    .circle1-box {
      width: 200px;
      height: 200px;
      overflow: hidden;
    }
    .circle1 {
      width: 1px;
      height: 1px;
      border: 199px dotted bisque;
    }
    .border {
      padding: 20px 0;
      width: 30px;
      height: 9px;
      border-top: 9px solid;
      border-bottom: 9px solid;
      background-color: currentColor;
      background-clip: content-box;
    }
  </style>
</head>
<body>
  <div class="triangle"></div>
  <div class="triangle2"></div>
  <div class="triangle3"></div>
  <div class="triangle4">
    <div class="triangle41"></div>
    <div class="triangle42"></div>
  </div>
  <div class="circle"></div>
  <div class="circle1-box">
    <div class="circle1"></div>
  </div>
  <div class="border"></div>
</body>
</html>